The present invention relates to a fastener system, and more particularly to a fastener system which secures a composite panel to a noncomposite support structure.
Aerospace/industrial gas turbine engine (GTE) applications and hypersonic propulsion systems include several component assemblies which are exposed to high temperatures. Among these component assemblies are combustion chambers, exhaust nozzles, afterburner liners and heat exchangers. These component assemblies may bound a portion of a gas path that directs the combustion gases through the engine and are often constructed of heat tolerant materials. Ceramic matrix composites (CMCs) are one class of materials which possess the requisite heat tolerance properties for these applications. CMCs typically include materials of carbon or silicon carbide fibers in a carbon or silicon carbide matrix.
Although CMC components provide significant heat tolerance properties, the CMC materials alone may not withstand the severe mechanical and structural demands of these applications. Often, a noncomposite support structure is utilized with the heat tolerant CMC structures to form the component assemblies. The CMC structure heat shields the noncomposite support structure to maintain the noncomposite support structure within operational temperature limits.
The CMC structure is commonly secured to the noncomposite support structure with mechanical metal or composite fasteners, CMC “T” joints, Miller fasteners and round braided fasteners. Although effective, each current fastener system may result in specific design constraints which need be accommodated by the component assembly. Current fastener systems may also have to contend with leakage around the fastener and tolerance control issues. Furthermore, fastener systems for certain applications may require that the fastener system be flush as any portion that may otherwise project into a combustion gas path may introduce undesirable turbulence and be subject to foreign object damage.